main() {
    var name = '枸杞';
  print(name);

  name = '张三';
  print(name);

  var num = 15;
  print(num);
  num++;
  print(num);

  const age = 19;
  print(age);
  final num1 = num + 15;
  print(num1);
  const PI = 3.14;
  print(PI); 
}
